Manufacture of electric mercury bulb switches



Aug. 16, 1932. 1. E. M CABEET AL 1,372,070

MANUFACTURE OF ELECTRIC MERCURY BULB SWITCHES Filed May 29,1929 4 Sheets-Sheet 1 INVENTOR )R!\ E. M CABE AND BY vKARL. HU \KER. Al M ORNE Aug. 16, 1932. M cABE ET AL V 1,872,070

MANUFACTURE OF ELECTRIC MERCURY BULB SWITCHES Filed May 29, 1929 4 Sheets-Sheet 2 26 INVENTOR IRA E. M CABE AND BY KARL H NCIKER 4a.

A ORNEY' Aug. 16, 1932.

l. E. M CABE ET AL MANUFACTUREOF ELECTRIC MERCURY BULB SWITCHES Filed May 29, 1929 4 Sheets-Sheet v 3 INVENTOR lRA E.MGCABE AND B A0 KARL HUNCMER ATTORNEY Aug. 16, 1932. E. M CABE ET AL MANUFACTURE OF ELECTRIC MERCURY BULB SWITCHES Filed May 29, 1929 4 Shee-tsSheet 4 Mm 8 W INVENTOR C BE AND KARL HUNCIKER BY 5% I GWM/ M ATTORNEY [RA ELM Patented Aug. 16, 1932 UNITEDFSTA'TES in E. MCCABE Ann KARL HUNGIKERbF CHICAGO, ILLIllTOIS MANUFACTURE OF ELECTRIC glamour Buns swI'rCHEs v Application fi1ed'May 29, 1929. Serial m5. 366,916.

This invention relates to improvements in the manufacture of electric mercury bulb switches and more particularly to the method and automatic apparatus for producing the mercury bulb switches as disclosed in my copending applications, Serial Nos. 329,548 and 358,225 filed December 31, 1928 and April 26, 1929, respectfully, in which the electrodes of a glass bulb, the sides brought together to seal the electrodes and filling stem and support the electrodes in proper positions in one operation, whereby the bulb switch is a prepared for the insertion of the mercury or other electrical conducting fluid, the exhausting of the air, and substitution of the gas to reducev arcing are accomplished through the filling stem which is then tipped off.

It is an object of this invention to provide an automatic apparatus which through suc-' cessive steps produces the bulb switch ready for the reception of the conducting fluid and gas in a prompt and uniform manner and in addition thereto shapes the bulb adjacent the sealed end, at the same time, to insure that the electrodes projecting into the interior ofthe" bulb are not contacted by the wall of the bulb.

While it is old in the manufacture of electrlc light bulbs to produce pinch seals and provide filling stems, the accuracy in locating the electrodes is not so vital as in mer cury tube or bulb switches and, while the filling stem is ordinarily, in this art mentioned,

provided at the end opposite the seal, the

stem has not been employed for shaping the bulb during the sealing process.

The method and apparatus disclosed here- 4.0 in produces a uniform product automatically at much less expense than heretofore, inasmuch as the machine accomplishes the result without manual operation thereby avoiding the variations naturally resulting between the products of individual manual operators.

0 and a filling stem are inserted in the open end With these and other objects in View, reference is made to the accompanying sheets of drawings which illustrate preferred forms of' this invention, with the understanding that minor detail changes may be made Without departing from the scope thereof. In the drawings:

Figure lis a fragmentary top plan view illustrating the essential elements of the apparatus to carry out the steps of this invention.

Figure 2 is a view in side elevation of an electric mercury bulb switch as produc'ed'by the operation of the apparatus illustrated in Figure 1.

Figure 3 is a detail view inside elevation, with parts broken away, illustrating the bulb holder when in position between the first heating gas jets.

- Figure 4 is an enlarged detail-view of the bulb holder, partly in section and partly in elevation, looking at the same from the exterior of the rotating member or'turret, before heating.

Figure 5 is a top plan view of Figure 4.

Figure 6 is a detail view in central vertical section of the electrode support.

Figure 7 is a top plan view of the filling stem core catch, with parts in section taken on the line 7-7, Figure 4. 1

Figure 8 is a view similar to Figure 4 il lustrating the position of the sealing jaws in the act of sealing the bulb. t

Figure 9 is a view similar to Figure 4-illustrating the parts after the sealing has been accomplished, and the filling stem core withdrawn.

Figure 10 is a top plan view showing the separate parts of one type of bulb switch before they are assembledby the apparatus.

Figure 11 is a.-view in side elevation of the assembled bulb switch embodying the parts shown in Figure. 10. I

Figure 12 is a view in end elevation of Figure 11. 90

moved from the apparatus.

Figure 13 is a view in side elevation of a. modified form of bulb holder, with the sealing jaws closed.

Figure 14 is a detail plan view showing the jaws of Figure 13 in engagement with the Figure 18- illustrates a modified form of sealing jaw.

In accordance with this invention, the apparatus, in a preferred form, is illustrated in Figure 1 for producing the form of electric mercury bulb switch shown in Figure 2. The apparatus includes. arotating table or turret 1 upon which are mounted adjacent its circumference preferably eight equally spaced bulb holders, generally indicated by the reference numeral 2. The turret 1 includes mechanism, not shown, for. imparting a step by step motion to it, with a predetermined equally timed halt at each step. As this mechanism is old in this art there is no need in describing it in detail. Gas ,jets 3, arranged in pairs and connected by pipes 4 to a source of gas supply, are held to direct their flames from opposite sides of the bulb holder during four successive halts of the turret 1. Considering the lowermost part of Figure 1 as the front of the apparatus faced by the operator, the'first pair of gas jets 3 is arranged two steps or halts to the right therefrom and the third pair of gas jets 3, or pair opposite the operator, is preferably increased by two additional jets 5, on each side of the bulb holder, for a purpose hereinafter described.

The bulb holders are all of the same construction as shown in detail in Figures 4 to 9 inclusive. Each includes a shouldered cy-.

lindrical base 6 adapted to be engaged and supported upon the turret 1. Supporting arms 7 support a work holder guide 8 between them, provided pivotal points for the sealing aws 9 and support the bifurcated arms 10 for the bulb holding clamp.

One type of mercury bulb electric switch as formed in accordance with this invention is illustrated in Figure 2 after it has been re- The parts that go to make up another type of this switch are illustrated before assembly and sealing in Figure 10. Referring to Figure 10, the glass bulb 11 is of tubular form closed at one end and open at the other. The filling stem 12 is preferably of greater length than the bulb and is a glass tube of small diameter, The electrodes 18 are welded to leading in wires 14 of a material that will seal in glass.

There' may be two, three or four electrodesdepending upon the type of switch. 7 Figure 2 illustrates two spaced apart electrodes arranged in the plane passing through the longestdimention of the sealedend of the bulb 11, while Figure 10 shows one electrode supporting a cup of insulating material and other adapted to be terminated in said cup, as shown in Figure 11.

The work holder guide8 is supported in axial alignment with the base 6 and has a central bore 15 adapted to receive and support the filling stem 12. A wort holder '16 is removably supported above the guide 8 and is provided with a central bore through which the filling stem is adapted to pass and with electrode supporting and positioning recesses 17.

In order to prevent the filling stem being collapsed and closed during the sealing operation, a core 18 is mounted to reciprocate within the guide 8 and filling stem when contained therein. The core 18 passes through the bottom of the guide 8 and into a recessed shaftaxially mounted within the base 6, the purpose of which will be hereinafter described. The core 18 is provided with a shoulder 19 which is normally held against the lower extremity of the guide 8 by a spring 20 within the said recessed shaft with the upper portion normally extending through the seal when completed. The bottom of the bore 15 in' the guide 8 below the stem sup port communicates .with an angular fluidpipe 21, the purpose of which will be hereinafter described.

' The bifurcated arms 10 support spring pressed pivoted bulb engaging jaws 22 provided with a manual release plunger 23. These jaws'are adapted to engage a bulb 11 and support is axially above the guide 8 with its open end embracing the filling stem 12 and leading wires 14 of the electrodes when supported in the work holder 16. \Vhen the embracing wall of the bulb 11 becomes sufiiciently plastic to be compressed the sealing jaws 9 are caused to operate opposite sides of and compress the plasticwall together to embrace, and seal the leading in wires 14 and filling stem 12 within the closure so formed. This movement is imparted to the sealing jaws 9 y pivoted links 24 pivoted at their lower ends to a bracket 25 mounted upon the recessed shaft 26 which shaft is mounted to reciprocate within the base 6 and which extends t herebelow. The jaws 9 are normally held in open position by springs 26 secured to the links 24 and shouldered portion of the base 6. The bracket 25 also supports a spring pressed catch 27 adapted when the shaft 26 is in its uppermost position with the jaws 9 closed to'engage a shoulder 27, upon the core 18 and withdraw the core as the shaft 26 moves downward. The catch 27 is provided with a release arm 28 to release the core 18 iao after the formed bulb switch has been removed.

The step by'step movement ofthe turret 1.

the reciprocation of the shaft 26 and release of the catch 27 may be manually controlled or by automatic, as desired. A supply of filling stems 12 of uniform length, a plurallty of work holders 16 with leading in wires 14: attached to the electrodes 13 supported therein, as well as a supply of glass bulbs 11 are kept available to the operator who faces the apparatus. When the turret halts with an empty bulb holder 2 in front of him, a work holder, with the supported electrodes, is placed upon the guide 8 and a filling stem 12 placed with the bore 15 and the work holder is manually adjusted to position the electrodes in proper relation, if need be, by a projecting finger 29 on the work holder. Then the jaws 22 are opened .by the manual release 23 and a bulb 11 placed in proper relation to the electrodes and filling stem and the jaws closed. The turret moves, or is caused to move to step onward and another empty bulb holder 2 is brought in front of the operator and filled in the manner described. On the next step onward the turret carries the first bulb holder 2 between the flames of the first pair of gas jets 3. The nozzles of these gas jets 3 are so formed and arranged as to project a suitable fiat flame on opposite sides of the bulb 11 adjacent its open end as shown in Figure 3 and during the halt of the bulb holder 2 between this first pair of jets an initial heating of the open end of the bulb 11 is accomplished and on the next step onward the holder is brought between a simliar pair of gas jets 3 and the bulb is further heated during this halt of the turret.

As the holder 2 reaches a position diametrically opposite the operator at its next halt, the bulb 11 is brought between the three pairs of gas jets 3 and 5 and at this point the open end of the bulb 11 becomes sufficiently plastic to be sealed and just before the turret moves on the sealing jaws 9 are caused to operate to compress the plastic open bottom of the bulb 11 to embrace and seal the leading in wires 14 and filling stem 12 in the closure -so formed with the stem 12 opening into the closed bulb and held against closing by the core 18. As or before the turret moves to the next halt the jaws 9 are caused to open and as the shaft 26 descends the catch 27, which on its upward. movement engages the shoulder 27 upon the core 18, will withdraw the core 18 from that portion of the filling stem 12 embraced in the sealed end of the bulb 11. On the next halt, the holder 2 steps between a pair of gas jets 3 and at the same time the enlarged opening 29 of the air pipe 21 is brought in the path of a desired fluid, gas or air under pressure issuing from the nozzle 30 upon a pipe 31 leading from a source, not shown. At this halt, the seal is cooling from of the sealed closure will normally deform the cylindrical sides of the bulb 11 but the 1 air entering through pipe 21 and filling stem 12 into the interior of the sealed bulb 11 will increase the. internal pressure within the -sealed bulb sufficiently to maintain an even contour of this lower portion adjacent the seal. At the next halt the sealed bulb 11 cools. At the following halt it is sufficiently cool to maintain its shape and is removed and preferably placed in an annealing furnace, not shown. After the sealed bulb 11 has been removed the holder reaches its starting position where another set of parts are inserted, and preferably before reaching the first set of jets 3, the catch arm 28 is moved to release the cat-ch 27 from engagement with the shoulder 27 and allow the core 18 to assume its normal position. When the sealed bulb 11 is removed from the apparatus it is preferable to also remove the empty work holder 16 so the holder 2 asit arrives in front of the operator is ready to be loaded and continue through another cycle.

The bulb holders 2 heretofore described and illustrated in Figures 1 and 2 to 9, in-

clusive, are of the type employed in sealing the bulb 11 about two electrodes in a plane passing axially through the bulb 11 with the filling stem arranged in the axis thereof, as shown in Figures 2, l1 and 12. The two oppositely compressing and sealing jaws 9 are brought together by the links 24: so that they engage opposite plastic portions of the bulb 11 and press them toward each other and by the time the projections 9 on one side of each jaw is brought into engagement with the fiat surface of the other jaw the plastic wall is caused to embrace, embed and seal the leading in wires and filling stem and the open end of the bulb iscompletely closed and sealed.

Figures 13 and 14 illustrate the bulb holder employed in producing a. seal forthe bulb switch. shown in Figures 15 and 16 in which four leading in wires are arranged equidistant from the longitudinal axis of the bulb 11 with the filling stem arranged axially thereof. In this form, the seal is formed. byv providing four. compressing and sealing jaws 9 actuated by links 24 in the same manner as heretofore described. ing portion of the jaws are so formed that when the two pair of oppositely disposed jaws are brought together they will simultaneously engage four points of the plastic wall of the open end of the bulb 11 and simultaneously compress them to cause the adjacent portions to fold about, embrace and seal each respective leading in wire until the projections 9 on each side of each jaw engage each other, and at the same time surround and seal the filling in stem. Of course,

let

The compresstrodes sealed in the end closure, it is customary to either provide the electrodes with enlarged interior ends as shown in Figure 2 or construct one electrode to support an insulating cup with theother electrode terminating within the cup as shown in Figures 10 and 15. In both cases, it has been necessary to use great care in forming the sealed closure so that no part of an electrode or insulating cup touches the bulb wall. This invention provides for this contingency by admitting air under a predetermined pressure while the wall of the bulb adjacent the sealed end is sufiiciently plastic to be shaped by the internal pressure so created to positive- 1y clear either the enlarged electrode or insulating cup.

Figure 17 illustrates a modification in the filling stem core in which that portion of the filling stem core which is normally contained within the guide 8 before the closure is made, is provided with a longitudinal passage-way 18 and the core below the filling stem 12 when contained within the guide and before the core has been withdrawn, is provided with a series of slots or passage-ways 18 whereby air under pressure entering through the pipe 21 into the bore 15 below the filling stem 12 is conducted through the slots 18 and passage-way 18 in the core 18 to the interior of the bulb 11. W hen this type of filling stem core 18 with the passage-way 18 is employed it is not necessary to withdraw the core before the air is admitted to shape the lower wall of the bulb 11. In some cases it may be desirable to provide the upper sides of the jaws 9 with molding or shaping portions9 so that when the air is added to the interior of the bulb 11 before the jaws are removed, these portions 9 will act as a mold to shape the plastic portions above the seal and pre vent an excess pressure of air from blowing therethrough, as shown in detail in Figure 18. This latter arrangement would allow the omission of some of the heating steps which would also shorten the period of operation.

Electric bulb switches formed in accordance with this invention are more uniform in construction'because each step is carried out automatically, mechanically performed in the same manner and at the same time, and the steps are not dependent upon the temperament of various individual operators. An apparatus of the character described will produce bulb switches at a uniform rate and in greater numbers during agiven time than can be produced by hand. This invention not only increases production, lessens the cost of manufacturebut also insures a uniform product.

What I claim is:

the bulb is still plastic and 1. The method of producing electric bulb mercury switches which includes posltionlng of the open end of the bulb about the electrodes and a filling stem containing a removable oore supported thereunder, applying heat to the open end of the bulb untll it becomes plastic, compressin the plastic wall to embrace, embed and seal the electrodes and filling stem therein and form a sealed closure, and thereafter removing the core while b owing through the sealing stem and thereby returning and maintaining the normal shape of the bulb.

2. The method of automatically producing electric liquid contact bulb switches by machinery including a step by step movement in which the first step consists in locating and positioning electrodes witha filling stem containing a removable core interposed between the electrodes and positioning and supporting the open end of ab'ulb thereabout, then through the next succeeding steps pass the open end of the bulb between gas flames playing on oppositely disposed walls thereof and when sufliciently plastic compress the plastic walls about the contained electrodes and filling stem to embed the same and form a sealed closure for the "bulb with the electrodes extending within the interior and remove the filling stem core to provide an opening into the interior of the sealed bulb, admit air under pressure to the interior of the bulb to return and maintain its normal contour and in the next succeeding steps reduce the temperature of the seal, and lastly remove the completed structure fro the machine.

3. The method of automatically producing electric liquid contact bulb switches by machinery including a step by step movement in which the first step consists in locating and positioning electrodes with a filling stem containing a hollow removable core interposed between them and positioning and supporting the open end of a bulb thereabout, the-n through the next succeeding steps pass the open end of the bulb between gas flames playing on oppositely disposed walls thereof and when suificiently plastic compress the plastic walls about the contained electrodes and filling stem to embed the same and form a sealed closure for the bulb with the electrodes extending within the interior and the filling stem opening therein, admit a1r under pressure to the interior of the bulb through the hollow core to return and maintain the normal shape of the bulb, remove the core, and in the next succeeding steps reduce the temperature of the seal, and lastly remove the completed structure from the machine.

l. The method of automatically producing electric liquid contact bulb switches by -.,machinery including a step by step movement in which the first step consists in locating and positioning electrodes with a filling stem con- 1 taining a removable core interposed between the electrodes and positioning and supporting the open end of a bulb thereabout, then through the next succeeding steps pass the open end of the bulb between gas flames playin on oppositely disposed walls thereof and w en sufficiently plastic compress be- 7 tween molds the' plastic walls about the contained electrodes and filling stem-to embed 10 the-same andform a sealed closure for the bulb with the electrodes extending within the interior and remove the filling stem core to provide an opening into the interior of the sealed bulb, admit a r under pressure to the interior of the bulb to mold the plastic wall above the closure out of contact with the electrodes, and in the next succeeding steps reduce the temperature of the seal, and lastly remove the completed structure from the machine.

5. The method of automatically producing electric liquid contact bulb switches by machinery including a step by step movement in which the first step consists in locating and positioning electrodes with a filling stem containing a hollow removable core--interposed between them and positioning and supporting the open end of a bulb thereabout, then through the next succeeding steps pass the open end of the bulb between gas flames playing ,on oppositely disposed walls there of and when sulficiently plastic compress between molds the plastic walls about the contained electrodes and filling stem to embed the same and form a sealed closure for the bulb with the electrodes extending within the interior and the filling stem opening therein, admit air under pressure to the interior of the bulb through the hollow core to mold the plastic wall above the closure out of contact with the electrodes, remove the core, and in the next succeeding steps reduce the temperature of the seal, and lastly remove the completed structure from the machine.

6. The method of producing electric bulb mercury switches which includes the positioning of the open end of the bulb about the electrodes and a filling stem containing a removable core supported thereunder, applying heat to the open end of the bulb until it becomes plastic, compressing the plastic wall to embrace, embed and seal the electrodes and filling stem therein and form a sealed 55 closure, and removing the core while the bulb is still plastic and b owing throu h the filling stem to return and maintain t 0 normal shape of the bulb.

' IRA E. McGABE.

KARL HUNCIKER. 

